Engines 6: Electrical Systems Flashcards
Describe DC power.
Electrical current that flows in one direction
What are the disadvantages of DC components?
Heavy
Unreliable
Require increased maintenance
What are the DC components?
DC generator
Transformer-Rectifier
Battery
Describe AC power.
Electrical current that reverses it’s direction of flow
What are the advantages of AC components?
Lightweight
Simple
Reliable
AC components are lighter because they require less current (due to high voltage) which reduces the amount of wiring needed in the aircraft
What are the AC components?
Alternator (AC generator)
Inverter
What type of power do generators produce?
Can produce DC power or AC power (depending on the generator type)
What does a constant speed drive (CSD) do?
It is a hydro-mechanical linkage that ensures a constant input rpm to the generator regardless of engine rpm
The constant input rpm means that there will be a steady output voltage to supplied equipment
What is an inverter?
A device that transforms DC power into AC power
What is a transformer-rectifier?
A device that transformers AC power into DC power
What is a battery?
A device that provides DC power
What is the purpose of a battery?
To act as an emergency source of power
Used to start the aircraft engines
What is a bus?
The pathway between different energy sources
What are the four types of busses?
Essential Bus
Primary Bus
Secondary Bus
Starter Bus
What equipment does the Essential bus supply power to?
Equipment needed for safety of flight
(primary attitude gyroscope)
What equipment does the Primary bus supply power to?
Equipment needed for aircraft mission
(radar)
What equipment does the Secondary bus supply power to?
Equipment needed for convenience
(cabin lighting)
What equipment does the Starter bus supply power to?
Equipment needed for starter circuits to start the aircraft engines
What provides an automatic means of interrupting power?
Circuit breakers
Fuses
What provides a manual means of interrupting power?
Circuit breakers
Switches
What will signal a electrical system malfunction?
Warning lights in the cockpit
What is an auxiliary power unit?
A small, independent gas turbine that ultimately turns a generator that provides power to the aircraft
When is the APU needed?
For emergency power
Power during ground operations
If the main generator fails, which bus(ses) will remain powered?
The essential bus
